Above-ground storage tanks (AST) experience external corrosion from atmospheric exposure, internal corrosion from stored products, and stress from product loading variations. API 653 establishes inspection intervals and methodologies enabling detection of degradation before failures occur. Ultrasonic wall thickness scanning at systematic locations establishes baseline thickness and enables trending of corrosion rates.
External surface visual inspection identifies coating degradation, obvious corrosion damage, and structural distortion. Foundation condition assessment evaluates settlement or deterioration that might compromise tank structural integrity. Internal inspection through manhole openings reveals internal corrosion patterns, sediment accumulation, and equipment condition. API 653 certification ensures inspectors understand AST failure mechanisms and appropriate assessment methodologies.
Remaining useful life calculations based on measured thickness and established corrosion rates inform replacement planning. NDT consulting services develop defensible arguments for continued operation of aging ASTs when technical analysis demonstrates adequate safety margins.
Comprehensive AST inspection programs prevent failures that might otherwise result in product loss, environmental contamination, and regulatory enforcement actions costly to resolve.